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(No Moael.) 2 sheets-sneer. 1. H. KLUEPFBL.

PINE FUEL PURNAGE.

No. 516,652. f Patented Mar. 20,1894.'

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(No Model.) 2 sheets- Sheet 2. H. KLUEPFEL.

FINE FUEL FURNAGE.

No. 516,652. i Patented Mar. 20, 1894.

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FINE-FUEL FURNACE.

SPECIFICATIONv forming part of Letters Patent' No. 516,652, dated March20, 1894.

Application filed October 31, 1893. Serial No. 489,619. (No model.) l

To all whom t may concern,.-

Be it known that I, HERMANN KLUEPFEL, a subject of the King of Prussia,residing at Barmen, in ,the Kingdom of Prussia, Germany, have inventednew `and useful Improvements in Furnaces for Pulverulentand Fine-GrainedFuel, of which the following is a specification.

This invention relates to furnaces for burning pulverulent or iinelydivided fuel, as coal dust, and aims to provide certain improvements indevices of this character.

To this end, in carrying out the invention in its preferred form, Iprovide a receiver for the fuel, a conveyor, communicating with saidreceiver for carrying the fuel to the point of delivery, an air blastfor conveying the fuel to the point of combustion, means for controllingsaid blast, a valve for controlling the supply of fuel, and preferably amovable i frame or plate carrying said parts and serving as the frontplate of the furnace and movable upwardly above the furnace to giveaccess to the interior thereof, and a movable grate within the furnacefor use previously to the ignition of the powdered fuel and removabletherefrom beneath said plate when the latter has been raised.

In the accompanyingdrawings, Figure l is a vertical axial section of aliame tube boiler to which the preferred form ofl my improvement isapplied. Fig. 2 is a front elevation thereof, the fuel feeding apparatusbeing in vertical section. Fig. 3 shows in axial section, and in threeend views, three different shapes of removable mouth pieces for fuelconveyers. Fig. 4 is a section of such a mouth piece having a swingingthrottle valve. Fig. 5 is a vertical axial section of a mouth piece ofthe construction shown in Fig. l but having an vaxial longitudinallyadjustable cone throttle valve within the fuel conveying pipe.

Referring to the drawings let B represent the receiver for the fuel, sbars carrying the receiver, P a plate engaging said bars, closing'theflame tube at front of the boiler, Z the air supplying tubes which arecarried by said plate, F the fire doors provided with the usual dampersand carried by said plate, k conveying pipes connected to andcommunicating with the receiver at top and opening into the tubes Z atbottom, M nuts fixed to the plate P, S screw spindles engaging thesenuts, H a hand wheel for operating the screws S, T bevel gears betweenthe screws and hand wheel, Z the grate frames, and r the grate bars. dis a valve for controlling the iiow of fuel, c a similar valve for alike purpose, f a valve for controlling the air supply, and o a 6o peepaperture in the latter valve.

The receiver B may be of any suitable construction, and may have one ormore fuel conveying pipes lc communicating with its under side andleading to the air current pipes l. A suitable valve is provided forcontrolling the flow of fuel from the receiver. Preferably a valve clarrangedv axially of lthe discharge mouth of each pipe k, and disposedwithin the air pipe Z is provided, which 7o valve can be moved toward orfrom the pipe 7c to control thelarea of the annular discharge spacebetween the mouth of this pipe and the valve, and thereby determine thefeed of the fuel. If desired, however, a valvec within the pipe lo maybe used, either alone or in conjunction with the valve d, forcontrolling the speed of supply of the fuel.

According to one feature of my invention I construct the internal wallsof the receiver, 8o the fuel conveying pipes, and the-external walls ofthe valve or valves d and c, at an angle ofvinclination relatively tothe horizontal which is steeper than the natural angle of slope of thefuel. This is an important feature, for the reason that pulverulent orfinely divided material willnot move under the action of gravitationover an inclined plane the inclination of which is less than the naturalangle of slope of the fuel, but will in such a 9o case adhere to or restupon the wallor plane and eventually prevent the passage of subsequentfuel thereover. With'my invention I construct the walls with such steepinclinations that none of the powdered fuel will adhere thereto, it allpassing freely thereover under the action of gravitation. I alsoconstruct the walls of the valves d and c with like inclinationspreferably the reverse of the inclination of the walls of the pipes lo.

The receiver B, bars s, and plate P, constitute essentially a movableframe carrying the fuel feeding and draft controlling apparatus. Thisframe is manipulated to Aopen or close too the flame tube of the boilerby means of the screws S, or in any other suitable manner.

According to another feature of my invention the powdered fuel isdischarged into a gaseous current or blast, preferably an air currentinduced by the usual draft of the furnace, and this current serves toconvey the fuel into the flame tube of the boiler, suitably subdividingthe fuel and intermixing the air or gas with it, and I provide means forcontrolling this current. Preferably this is accomplished by providingan air pipe Z carried by the plate P, and opening into the flame tube,and an air valve f at the outer open end of this pipe movable to open orclose the same for 'controlling the flow of current therethrough.

Another feature of the invention consists in providing a removable grateframe Z carrying the grate bars r, which frame ridesinto the fiame tubeon rollers Xengaging tracks V therein, and is inclosed therein by theplate P when the latter is down. This frame can be withdrawn from thefurnace, when combustion of the powdered fuel is well under way, orpreferably when the furnace is sufficiently heated to ignite thepowdered fuel when the latter is fed thereto, by raising the plate P anddrawing out the grate frame.' 'The grate frame is usually loaded withordinary fuel, which is ignited and burned in the flame tube until therequisite heat has been generated therein to ignite the powdered fuel,whereupon the frame may be withdrawn and the powdered fuel fed to thefurnace.

In operation the powdered fuel is placed in the receiver B, the valvefor controlling the discharge through the pipes 7c is closed, thetemperature of the fiame tube is raised by ordinary fuel on the grateframe Z, the plate P and feeding apparatus are then raised and the grateframe withdrawn, the plate and feeding apparatus are then restored, thevalve controlling the feed properly adjusted, and the operation ofburning the powdered fuel then commences. In this operation theconveying pipes 7c discharge preferably an annular stream of powderedfuel into the air pipe Z, and the current through the latter takes upthe powdered fuel, subdivides it, mixes with it, and carries it into thecombustion chamber or fiame tube, where it is ignited either by the heatalready generated therein as before described,or in any suitable manner.A continuous and regular flow of powdered fuel follows, which may becontrolled by adjusting either the fuel valve CZ or c, or both. The aircurrent maybe controlled by the air valve f. The operation may beobserved through the aperture o. The draft maybe controlledA by thedoors F.

Preferably the apparatus is constructed with one receiver B having threeconveying pipes Zr., each having a separate air pipe Z, and the dametube is partly lined internally with fire brick, or other refractorymaterial, up to beyond the fire bridge, in order to protect the walls ofthe boiler against projecting jets of flame. j

It will be seen that my invention provides an improved furnace in whichpowdered fuel can be readily and conveniently utilized, and it will beunderstood that the invention is not limited to the precise details ofconstruction and arrangement set forth in its preferred form, as it maybe availed of according to such modifications as circumstances or thejudgment of those skilled in the art may dictate, without departing fromthe essential features of the invention. I

Preferably the mouth pieces or conveying pipes 7c are removable so thatdifferent sizes and forms can be employed. Several forms are shown inFig. 3. To facilitate the removal of the mouth pieces they areconstructed at their lower ends to fitcorresponding sockets in the topsof the air pipes Z, and the discharge outlets from the receiver areadapted to pass into the upper ends of the pipes 7c, and are screwthreaded above these ends, and carry a nut screwing down on the pipes tohold them in position, as shown 1n Fig. l. Preferably a threaded handwheel engages the screw threaded stem of the valve CZ, and is carried atthe under side of the air tube Z for adjusting this valve. A similaradjusting device is provided above the valve c and carried by a framethereover. With each of these adjusting devices a suitably arranged markor graduation may be provided to indicate the quantity of fuel fedthrough the valve in a given unit of time.

The air current will be regulated according to the quantity of fuel usedand the 'purpose for which the combustion is required. Ordinarily coldair may be employed, butfor some purposes, especially for meltingprocesses, it will be desirable to first heat the air.

1. In a furnace for burning finely divided fuel, the combination withthe combustion chamber, of a receiver for the fuel, a discharge outletfor said receiver, a plurality of mouth pieces for said outlet, and airtube Z opening into said chamber and having a socket at top, said mouthpieces each fitting said socket in said tube at their lower ends, andeach fitting said discharge outlet from said receiver at their upperends, and constituting removable pipes communicating between saidreceiver and said air tube, whereby one can be substituted for another,substantially as and for the purpose set forth.

2. In a furnace for burning finely divided fuel, the combination with acombustion chamber of a front plate P therefor, an air tube Z carried bysaid plate, a receiver B for the fuel above said plate, a conveying pipeleading from said receiver into said tube for discharging the fueltherein, and a frame s carrying said plate and receiver and movablevertically to raise and lower said parts to give access to said chamber,substantially as and for the purpose set forth.

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3. In a furnace for burning finely divided fuel, a combustion chamberand a fuel feeding apparatus, in combination with a movable front platefor said chamber carrying said apparatus, and a removable grate frame insaid chamber opposite said plate, whereby ordinary fuel can be ignitedon said grate frame to heat said chamber to atemperature necessary toignite the finely divided fuel, and thereafter said grate frame can beremoved and the finely divided fuel fed to said chamber, where it willbe ignited by the heat thereof.

4. In a furnace for burning nely divided fuel, a combustion chamber, incombination with apparatus for feeding the finely divided fuel thereto,a front plate for said chamber carrying said apparatus and movablevertically relatively to said chamber to open and close it, and aremovable grate in said chamber for retaining the ordinary fuelrequisite to initially heat it, whereby when said front' plate is movedfrom said chamber said grate can be withdrawn therefrom, substantiallyas and for the purpose set forth.

5. In a furnace for burning finely divided fuel, the combination withthe combustion chamber 0f a receiver for the finely divided fuel, aconveying pipe k for discharging the fuel therefrom, and an airsupplying tube Z receiving the discharged fuel and opening into saidchamber, the inner walls of said conveying pipe constructed with aninclination steeper than the natural angle of slope of said fuel, and avalve for controlling the discharge through said conveying pipe andconstructed with walls of like but reversed inclination to those ofsaid` conveying pipe.

6. In a furnace for'burning finely divided fuel, a combustion chamber,in combination with a conveying pipe 7c for feeding the finely dividedfuel to said chamber, said pipe having inclined inner Walls, and a valvewithin said pipe, arranged axially thereof, movable in yverticaldirection for controlling the flow therethrough, and constructed in theform of a cone the outer walls of which are of the same but reversedinclination to those of said pipe.

In testimony whereof I have signed 'my name to this specification in thepresence of two subscribing witnesses.

HERMANN KLUEPFEL.`

Witnesses:

FRIEDR. SOHADDE, FR. SOHADDE, J r.

